The present invention is directed toward underwater cameras and more particularly to a pressure protection switch for use with underwater cameras in a flexible housing.
Various arrangements have been proposed in the past for taking underwater photographs. These have ranged from complex designs for cameras which have been constructed to be waterproof or waterproof housings which are simply adapted to incase a more conventional camera. Some underwater housings have been constructed of relatively rigid materials in order to withstand the significant water pressures which can build up underwater. These rigid or hard housings, however, require relatively intricate fittings, lever switches and the like in order to depress the shutter button from outside of the housing.
A much simpler type of housing which has also been used is a flexible plastic housing which totally surrounds the camera. The flexible plastic is substantially clear, at least in the area of the lens, and is flexible enough so that the shutter release button can be operated from outside of the housing directly through the housing by simply depressing the same.
Such flexible plastic housings have proven to be successful. However, at significant depths, the water pressure acting on the flexible housing can be so great that it can over power the spring return force of the shutter button so that when the button is manually depressed, it does not return to its original position.
The patent to Albrecht, U.S. Pat. No. 5,126,772, proposes the use of a seesaw means mounted in the vicinity of the shutter button with one end of the seesaw directly overlying the button. The stated purpose of this arrangement is to prevent water pressure from inadvertently depressing the shutter button. The seesaw device apparently acts to balance the water pressure by allowing the same to act on both ends of the seesaw thereby allegedly reducing pressure on the button itself.
At depths of 40 feet or more, however, flexible housings are no longer flexible due to the high water pressures thereon. As a result, a balancing function would not work due to the very tight holding grip of the flexible plastic housing around the camera body. Furthermore, even if there is a balancing effect taking place, the use of the seesaw in the Albrecht device increases the area on the flexible housing that can be pressed in order to activate the shutter, thereby making it possible for the operator to easily inadvertently activate the same. There is, therefore, the need for an underwater pressure protection switch which does not suffer from these deficiencies.